1. Field of the Invention
The present invention relates to a spraying device, particularly to a small spraying device which works by the piezoelectric effect.
2. Description of Related Art
Currently available small spraying devices mostly spray micro-particles by generating pressure variations, having a vibrating element and a spraying plate. Spraying plates are produced in two kinds, with the vibrating element being immersed in a liquid to be sprayed or connected with the spraying plate. When the voltage is applied to the vibrating element, a vibrating movement thereof ensues and is transmitted to the liquid to the spraying plate, so that liquid is pressed through tiny holes in the spraying plate and dispersed as micro-droplets.
Small spraying devices are used for various purposes, including burners, printer cartridges, perfume flasks and medical sprayers. To avoid contact of electrodes and electric circuits or with liquid that is possibly etching and potentially damaging piezoelectric material or needs to be kept pure, the vibrating element is usually kept separated from the liquid. Mostly, an insulating plate made of stainless steel is inserted between the vibrating element and the liquid, being glued to the vibrating element. Therefore, the liquid is driven indirectly by the vibrating plate, resulting in losses of vibrational energy, waste of energy and ineffective spraying.
Furthermore, conventional spraying devices are usually dismountable, so that upon a defect whole spraying devices have to be replaced, which is wasteful.